This is the driver diskette that came with the "Belkin 3 Button Combo Mouse," Belkin part number F8E201.
This is a generic mouse that's been badge engineered by belkin, but is really just a generic Mouse Systems/Microsoft Mouse mode hybrid serial mouse that can also work over PS/2 ports. There's a switch on the underbelly to control the two serial mouse protocol modes, labelled "PC AT" and "MS AM".
The chip inside is an HMC HM8450AP.
This upload includes a .zip file which has all the files from inside the floppy disk, as well as a raw floppy disk image (.img file) of the exact original contents and filesystem from the factory floppy disk. Use whichever appeals to you.
I bought this new old stock on ebay recently, decided it was worth uploading the drivers just in case.
Middle click only works in the "mouse systems" protocol mode. The Microsoft Mode (MS AM) works in Windows (9x, at least) without needing any drivers installed, however.
Label on the floppy reads:
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Mouse
Driver and Utilities
Driver for Dos, WIN3.1, WIN95
Type "A:\Readme" to access manual for different installation.
©1990 COPYRIGHT ALL RIGHTS RESERVED.
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The box art has a 1997 Belkin copyright date. Obviously, Windows 95 did not exist in 1990, so that's one more oddity of this package.
Curiously, the mouse on the box art does not show the belkin logo printed on the shell of the mouse itself, but my mouse does have the logo stamped on it (pad printed, I believe). Later versions of the box art did show the printing on it.